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Purple Sea Urchin

Posted on: December 12th, 2014 by Lisa Schall

(Arbacia punctulata)

A purple sea urchins pin cushion appearance comes from its round inner shell, called a “test.” The test is covered with pincers (pedicellariae), tube feet and purple spines that move on ball-and-socket joints.The spines spear food and protect an urchin from predators. Tiny hairs (cilia) covering the spines create a water current that carries food to the urchin and washes away wastes. An urchin uses its many tube feet to move along rocks, sand or other surfaces.They are only able to move at a rate of about 1-2 inches per minute. Surprisingly, an urchin also “breathes” through its tube feet—that’s where gases are exchanged, instead of in gills or lungs. If turned upside-down, they can right themselves by using their tube feet and specialized movements of their spines. The spines on the oral side (bottom) of their bodies are spatula-shaped spines that mostly aid in movement across sandy or rocky bottoms. If flipped upside down, urchins can right themselves through specialized movements of these spines.

Habitat

The purple sea urchin is usually found in intertidal and sub-tidal zones. They prefer shallow water on hard substrates like jetties, or pilings. They can be found along the coasts of North America from Massachusetts, southward to the Yucatan Peninsula.

Diet

The sea urchins are very important to their habitat because they help maintain the amount of algae in the ocean. They are actually considered the “grazers of marine algae.” They are omnivorous and will feed on seaweed and algae, sponges, coral polyps, and dead animals including dead urchins. Five tooth-like plates, called “Aristotle’s lantern, “surround an urchin’s mouth on the bottom of its shell. If food lands on an urchin’s back, the tube feet pass the food down to the urchin’s mouth like a bucket brigade.

Behavior

Purple sea urchins breed yearly from January through March and are ready to do so when they have turned two year of age. This reproduction process occurs through external fertilization during which males release their gametes into the ocean and fertilize the female’s eggs at random. The surf definitely aids in the transportation of the gametes, but too strong of a surf can damage the ova and spermatozoon. After fertilization, the egg matures and grows into a sea urchin. The test protects the sea urchins internal organs. However, the strengthening of the test must happen quickly to protect the sea urchin in its vulnerable state.

Predators

The spines on their dorsal (top) side are sharp and spike-like and are most often used in defense. Although sharp, these spines are quite brittle, can frequently break off during run-ins with potential predators. When shadows pass over an urchin, they have been observed to point their spines in the direction of the shadow, to protect itself from a potential predator. Sea gulls, triggerfish, otters, sea stars and wolf eels are all predators to the sea urchin.

Forbes Sea Star

Posted on: November 19th, 2014 by Lisa Schall

(Asterias forbesi)

Sea stars belong to a group called Echinoderms which means “spiny skin.” Scientists prefer to use the term ‘sea star’ and not ‘starfish’ because this animal is an invertebrate and not a fish. The Forbes sea star is also called the ‘common sea star.’  This star can reach about 5 inches in diameter and its coloration can be tan, brown, or olive with tones of red, orange and pink. The bright orange dot in the center of the body is called the madreporite. This organ pumps water into the sea star’s body. This pumping action creates suction at the end of hundreds of tube feet, located in paired rows on the underside of the arms. A sea star can move rapidly along the bottom by removing its grip, curling up its arms and drifting with the current or tide.When a sea star loses or damages an arm, it sheds the appendage at a point close to the center of its body and the cut skin begins to heal over. It then will regenerate a new limb. Sometimes a sea star will overcompensate and grow more than one replacement limb. On the end of each arm is a small pigment eye spot that is sensitive to light.

Habitat

The Forbes sea star is found from the Gulf of Maine to Texas. It lives predominantly on rock, gravel, or sand bottoms and is commonly found during low tide on rocky surfaces.

Diet

The Forbes’ sea star is a carnivore that feeds chiefly on bivalve mollusks in the wild. In aquariums, this animal will eat nearly anything. When feeding, a sea star will wrap its five arms around its prey gripping it with its suction cup like tube feet. The stomach, which looks like a thin white membrane, then extends through the mouth to surround the prey. The stomach tissue secretes digestive juices that dissolve the prey, which is absorbed by the stomach membrane. When preying on an oyster or clam, the sea star grips the bivalve’s shell and applies strong pressure to force it open. By creating even a tiny gap, the sea star can squeeze its stomach inside the shell and digest the soft body tissue.

Behavior

Sea stars breed in the spring, producing as many as 2,500,000 eggs. Females will feel plump and spongy when their arms are filled with eggs.

Predators

Sea stars are eaten by bottom-dwelling fish and crabs, as well as by sea gulls when low tides leave the sea stars exposed.

Common Spider Crab

Posted on: November 18th, 2014 by Lisa Schall

The Common Spider Crab is also known as the Portly Spider Crab or Atlantic Spider Crab. The shell or carapace of this crab is round and spiny, with nine small spines running down the center. This long, legged; slow moving crustacean is able to walk forward and side step (most crabs can only walk by side stepping.) The legs and pincers of the male spider crabs can be nearly twice as long as those of the females. The spider crab’s claws are different from those of other crab claws. They are narrow, long pincers that are slow and not as strong as other crabs; however, the larger males have big claws that can deliver quite a pinch. Spider crabs attach bits of algae, shell, and seaweed to the many fine, sticky hairs covering their bodies for camouflage. This is why they belong to a group known as decorator crabs.

 

Habitat

This spider crab can be found living in all types of substrates, but most commonly in bays and estuaries on mud and sand in the shallow water. They range from Nova Scotia, to south Florida, the Florida Keys and Gulf of Mexico.  These crabs are very tolerable to polluted or eutrophic environments, meaning environments where there is little oxygen.

Diet

Spider crabs are omnivorous and use the ends of their claws to scoop up bits of detritus and algae. Spider crabs are non-threatening and somewhat lethargic scavengers. They have poor eyesight; however, they do have sensitive tasting and sensing organs on the end of each walking leg. This allows them to identify food in the water or in the mud as they walk over it.

Behavior

Like all other crabs, spider crabs molt in order to grow. The females stop molting after they become sexually mature and remain the same size for the rest of their lives. The males typically grow larger than the females and can be up to 9 inches from claw to claw. They have been observed molting in large “pods” during the fall, hibernating in dense patches in the winter and mating in large groups during the spring. When the female is ready to release her eggs she is heavily protected by the male by being held behind him. The young hatch from eggs that are a bright orange-red when laid but turn brown during development, which takes approximately 25 days.

Predators

When startled, spider crabs will waive their pincers over their heads in a beckoning gesture to warn off potential predators. The main defense against predators is the use of camouflage by covering themselves with various spines and tubercles, algae, debris and small invertebrates. Gulls and other shore birds are the main predators as well as fish and sharks.

Coral

Posted on: February 28th, 2014 by wgoodman

Coral reefs are second only to rainforests in biodiversity of species. Despite how important coral reefs are to life in the ocean, all of them in the world add up to less than one percent of the sea floor – an area about the size of France. About 10 million bacteria can live on one square centimeter of coral.

Habitat

Coral reefs are found all around the world in tropical and subtropical oceans. They are usually found in shallow areas at a depth of less than 150 feet. However, some coral reefs extend even deeper, up to about 450 feet deep.

Diet

Coral polyps eat in two different ways according to the species. Many coral polyps are nourished by tiny algae called zooxanthellae (pronounced zo-zan-THEL-ee). The algae live within the coral polyps, using sunlight to make sugar for energy just like plants. Zooxanthellae process the waste of the polyp to retain important nutrients and in turn provide the polyp with oxygen. Meanwhile, the coral polyps provide the algae with carbon dioxide and a safe, protected home. Zooxanthellae living within the tissue of hard corals can supply them with up to 98 percent of their nutritional needs.

Another way that corals eat is by catching tiny floating animals known as zooplankton. At night , coral polyps come out of their skeletons to feed, making the reef look like a wall of hungry mouths. The polyps stretch out their long, stinging tentacles to capture the zooplankton that are floating by. The captured plankton are then put into the polyps’ mouths and digested in their stomachs.

Behavior

While corals may appear to be little more than stone or plants, these are in fact live animals related to jellyfish and sea anemones. Plants do play a very important role in the lives of corals though, most notably the symbiotic algae called zooxanthellae (ZOH-oh-ZAN-thell-ee) that live in their tissues. These single celled plants convert sunlight into energy that the corals use to grow, hence insuring a healthy coral polyp and colony overall. Most coral polyps have clear bodies and their skeletons are white, like human bones. Generally, their brilliant color comes from the zooxanthellae.

Coral reproductive methods vary according to the species. Some species, such as Brain and Star corals, are hermaphrodites, meaning they produce both sperm and eggs at the same time. Other corals, such as Elkhorn and Boulder corals, are gonochoric, meaning that they produce single-sex colonies. In these species, all of the polyps in one colony produce only sperm, and all of the polyps in another colony produce only eggs.

Coral larvae are formed in two different ways. The larvae are either (1) fertilized within the body of a polyp or (2) fertilized outside of the polyp’s body in the water. Fertilization of an egg within the body of a coral polyp is achieved from sperm that is released through the mouth of another polyp. The sperm and egg merge and matures inside the body of its mother. When the larva is ready, it gets spit out into the water through the mouth of its mother.

Other species of coral reproduce by ejecting large quantities of eggs and sperm into the surrounding water. When this happens, the eggs and sperm fertilize in the water. This process is called coral spawning. In some areas, mass coral spawning events occur on one particular night per year and scientists can predict exactly when this will happen.

Once in the sea, larvae are naturally attracted to the light. They swim to the surface of the ocean, where they remain for days or even weeks. If predators do not eat the larvae during this time, they fall back to the ocean floor and attach themselves to a hard surface. Once attached the larvae changes into a coral polyp and begins to grow. It divides itself in half and making exact genetic copies of itself. As more and more polyps are added, a coral colony develops. Eventually the coral colony becomes mature, begins reproducing, and the cycle of life continues.

Predators

Despite the importance of coral reefs, these wildlife habitats are in danger throughout the world. A recent report estimated that 75 percent of remaining coral reefs are currently threatened, and many have already been lost. Even some of the most remote and pristine reefs are losing species. The main threats to corals are ocean acidification, ocean warming and coral bleaching, water pollution, destructive fishing practices, coral mining, and careless tourism.

Pencil Sea Urchin

Posted on: February 28th, 2014 by wgoodman

Tan to dark reddish-brown in color, the pencil urchin has distinct thick, blunt spines that move in any direction. The spines are often coated with sponges or coralline algae. Pencil urchins have five similar parts that make up their test(body), or rigid skeleton, called pentamerous radial symmetry. These are five skeletal plates that equally cover their body.

Aristotle’s description of the sea urchin mouth, is the reason why it is termed as ‘Aristotle’s lantern’.

 Habitat

Pencil urchins are found in the Western Atlantic coastal areas from South Carolina to Florida and the Caribbean, as well as the eastern coast of Mexico to Brazil. Found in shallow waters, including coral reefs and rocky-bottomed areas near the low tide line and below.

Diet

Although primarily herbivorous, pencil urchins are opportunistic feeders and will scavenge for other types of food. They generally come out at night to feed, moving around and using their hard, horned teeth to scrape algae and other plant matter off rocks and corals. However, they’ll also eat sponges, barnacles, mussels and dead fish or other sea creatures.

Behavior

Despite males and females looking exactly alike, pencil urchins have distinct and separate sexes. They reproduce using external fertilization. Females release eggs and males release sperm into the water simultaneously, where they will join and become fertilized. Females can produce thousands, or even millions, of eggs in one go. Once hatched, these tiny urchins start out their lives as larvae and take roughly two years to reach their full adult size.

Predators

Predators of sea urchins are triggerfish and large wrasses, who nibble away at their spines before turning them over to eat the fleshy undersides.

Horse Conch

Posted on: February 28th, 2014 by wgoodman

Another common name for this snail is the Florida Horse Conch. It is the state shell of Florida. The Florida horse conch is the largest snail to be found in the American waters, sometimes reaching a length of two feet. Conchs belong to a class known as Gastropods, which make up the largest class of Mollusks. Conchs grow by increasing their swirling body while producing a protective shell. This shell protects their soft body from predators. They use a pad, or foot, that extends from their shell which allows them to drag their shell along. As they drag their shell often times their mouth and eyes can be seen coming out from the opening of the shell. In classic Mayan art, the Horse Conch is shown being utilized in many ways including as paint and ink holders for elite scribes, and also as a bugle or trumpet. In southern Florida, Native Americans, including the Calusa and Tequesta, used the horse conch to make several types of artifact. The whole shell was attached to a wooden handle and used as a hammer or woodworking tool. The body whorl was used as a drinking cup.

Habitat

Horse conchs are found from North Carolina to Florida and into Mexico. Commonly found in the sea grass beds and reefs in the Atlantic Ocean.

Diet

This snail is carnivorous and will feed on bivalves like clams and mussels as well as other snails.

Behavior

Reproduction is sexual. The female attaches capsule-like structures to rock or old shell. Each capsule contains several dozen eggs for the young snails to feed upon. The capsule contains 5-6 circular rims, and they are laid in clumps. The young emerge and are an orange color, approximately 3.5 inches in diameter.

Predators

Horse Conch predators are mainly humans that use them for their shells and for food. Other predators include octopus, they can use their suction cups to suck the conch out of its shell. Certain starfish are able to slip one of their arms into the operculum of the conch and will then force its stomach out and ingest the conch right from its shell.

Chocolate Chip Sea Star

Posted on: February 28th, 2014 by wgoodman

Like a chocolate chip cookie, this sea star has dark brown pointy horns shaped like chocolate chips all over the top of it for protection. The Chocolate chip sea star has a thick body with five thick radially symmetrical arms arranged around a central body disk, which contains all of the internal organs. Although sea stars are invertebrates, they have a skeleton. Their skeleton, however, is not made of bone. It is calcareous or made of a calcium-based rocklike substance. The skeleton is made up of small plates that easily move to give the sea star flexibility. Sea stars crawl across the seafloor using rows of tube like feet on their arms for locomotion. They use an internal plumbing system called the water vascular system. It is a system of water canals that run throughout the body. Water is sucked into the sea star through a small hole on the top of the animal. The ends of the canals can be found on the animal’s oral (underside) surface as tube feet. The tube feet move when there is a change in the water pressure within the canals. There are thousands of tube feet all over the sea star’s oral surface which are used for movement, capturing food and breathing. Sea stars can regenerate or regrow arms if they are bitten or ripped off by a predator or grow a new individual from a ripped off arm. Sea stars cannot see. They have an ‘eye spot’ on the end of each arm. The eye spot can detect changes in light and dark, but cannot make out distinct shapes, colors or details.

Habitat

Chocolate chip sea stars live in the warm areas of the Pacific Ocean, Indian Ocean and Red Sea. Found all over sea grass beds and sandy areas, these sea stars live in shallow water areas. They can also be found on coral reefs to depths of 100 feet.

Diet

They feed on sponges, coral, oysters, clams, algae, shellfish, bacteria and detritus or waste products and the remains of dead plants and animals. Since they do not have eyes, Chocolate Chip Sea Stars hunt using their sense of smell. Once they smell something they want to eat, the sea star carries itself over to its food. The mouth of sea stars is on the oral surface or underside of their body; the mouth lacks teeth. The star covers its food, then pushes out its stomach from inside its body and covers it. Stomach juices smother the food, and cilia or tiny hairs move its now gooey meal inside the sea star’s body. Sea stars have a unique adaptation for consuming bi-valve mollusks (oysters, clams, mussels, etc.). Stars insert a portion of their stomach into the small “gape” between the valves of a mollusk. Stomach enzymes are released and digest the fleshy part of the mollusk inside its own shell. The digested contents are moved back into the sea star leaving an empty bi-valve shell. Most bi-valve mollusks are at the mercy of sea stars, since their shells do not close perfectly.

Behavior

Chocolate Chip Sea Stars reproduce by spawning or releasing eggs and sperm into the ocean at the same time. Females can produce up to 65 million eggs per each spawn. Since the egg and sperm are spawned, fertilization or the joining of egg and sperm to form a tiny sea star is most likely to occur if a large number of sea stars have gathered in the same area and spawn at the same time. Sea stars go through five growth stages before coming to be the star-shaped animals with which we are familiar. During the first month, the sea star freely floats around looking like a tiny sea jelly or blob. It can barely be seen by the eye and feeds on tiny plants and animals floating in the ocean. The baby sea star then metamorphoses or changes shape into a star-shaped creature. For the next six months, the juvenile sea star slowly grows, finds a hidden home under reef rock and rubble, and begins feeding on algae. After they get big enough, these sea stars emerge and begin to travel the reef in search food. After two years the sea star stops growing and is developed enough to reproduce.

Predators

Although starfish are fairly well armored and generally ignored by most fish, several types of fish will view them as food, including triggerfish, pufferfish, boxfish and parrotfish. Also, other types of starfish are known to be cannibalistic and eat one another.

Moon Jellies

Posted on: February 28th, 2014 by wgoodman

Jellies also called jellyfish, are boneless, brainless and heartless, and are made almost entirely of water. They have been around since before the dinosaurs. When deprived of food they can shrink nearly 1/10th their size to save energy. They redevelop to normal size when food is available. Jellies are also related to coral and anemone.

Habitat

Temperate and tropical oceans worldwide; near the surface of shallow bays and harbors

Diet

Plankton, small shrimp, fish eggs, and larvae.

Behavior

Jellies eggs are fertilized when the female ingests floating sperm that were released by an adult male. When the female releases her fertilized eggs, they develop into a larval form which floats in the water until it finds a hard surface that it can anchor itself to. Once anchored it forms into a polyp (that resembles an anemone or an upside down jelly) and divides itself into a stacked series of saucer-like clones that then break off and swim away. As these forms called ephyra grow they form into adult jellies.

Predators

All seven species of Sea turtles include jellies in their diet. Other animals such as tuna, spiny dogfish, butterfish and ocean sunfish eat jellies as well.

Anemone

Posted on: February 28th, 2014 by wgoodman

Sea anemones are invertebrates that look like flowers, which is where their name comes from. However, sea anemones are animals, not plants, and are related to corals and jellyfish. Sea anemones are polyps made up of a soft cylindrical stalk of a body topped with an oral disc surrounded by tentacles. At their base, they have a single adhesive foot, called a basal disc, which they use to attach to underwater surfaces like rocks or shells. Anemones can have anywhere from a dozen to a few hundred tentacles. Sea anemones are known for their symbiotic relationships with other organisms. They may attach to the shell of a crab but they most noted for their relationship with the clownfish. The clownfish brings food to the anemone in exchange for protection. Most organisms that come into contact with the anemone are paralyzed by the stinging cells from the anemone’s tentacles but the clownfish is one organism that is able to live within the anemone without being eaten or stung. It develops immunity to the anemone and the clownfish must therefore remain with that same anemone for the rest of its life.

Habitat

There are numerous species of sea anemones that are found throughout the oceans at various depths. These cnidarians come in all colors, decorating a tide pool or reef like a garden of wildflowers. Most anemones usually stay in the same spot until conditions become unsuitable. Anemones are found worldwide in all marine habitats, at various depths. They can be found in a variety of temperature ranges from the cold water of the north Pacific to the warm water of the Caribbean.

Diet

Anemones are carnivores. Some feed on tiny plankton, and others feed on fish. The anemone has stinging tentacles, which are triggered by the slightest touch, firing a harpoon-like filament (called a nematocyst which is the same thing that causes a jellyfish sting) into their victim and injecting a paralyzing neurotoxin. The helpless prey is then guided into the mouth by the tentacles. The anemone has a single opening in the center of the oral disc, where food goes in and digested food comes back out.

Behavior

For the Sea Anemone, a complex process called lateral fusion is what takes place for reproduction. This involves the side of the entity opening up and then an identical part being created that is a second living one. They will release eggs and sperm into the water and then the sperm finds the eggs to fertilize them. This is how they take part in reproduction as well. However, only a very small number of their eggs will survive to the age of maturity. They are able to live attached to rocks or the bottom of the sea for up to 50 years.

Predators

Many species of fish, sea stars, and snails will opportunistically feed on anemones. Sea turtles have been known to feed on them, as well. The stinging cells of the anemone help to ward off some predators, but if an animal is big enough or clever enough, it can still make a meal out of an anemone.

Horseshoe Crab

Posted on: February 28th, 2014 by wgoodman

Horseshoe crabs are among the world’s oldest and most fascinating creatures. The earliest horseshoe crab species had already inhabited Earth at least 200 million years before the dinosaurs arrived or about 400 million years ago. Even though horseshoe crabs have a hard shell and numerous appendages with claws, it’s not really a crab. Horseshoe crabs belong to the phylum Arthropoda, along with crabs, insects, and other invertebrates with jointed legs, but their closest living relatives are spiders and scorpions. A horseshoe crab’s tail, while menacing, is not a weapon. Instead, the tail is used to plow the crab through the sand and muck, to act as a rudder, and to right the crab when it accidentally tips over.

 Habitat

They can be found in the Atlantic Ocean along the North American coastline. They can be seen along the East and Gulf coasts of the United States and Mexico. Horseshoe crabs utilize different habitat depending on the stage in their development. The eggs are laid on coastal beaches in late spring and summer. After hatching, the juvenile horseshoe crabs can be found offshore on the sandy ocean floor of tidal flats. Adult horseshoe crabs feed deeper in the ocean until they return to the beach to spawn.

Diet

The horseshoe crab spends most of its time rooting on the bottom looking for food.  Because they lack jaws, the horseshoe crab uses the spiny bases of their legs to crush and grind their food, then put it into their mouths. They eat mostly worms and mollusks such as razor clams, and soft shelled clams.

Behavior

Each spring during the high tides of the new and full moons thousands of horseshoe crabs gather along the beaches. Males, two-thirds the size of their mates, cluster along the water’s edge as the females arrive. With glove-like claws on its first pair of legs, the male hangs on to the female’s shell and is pulled up the beach to the high tide line.

The female pauses every few feet to dig a hole and deposit as many as 20,000 pearly green, birdshot-sized eggs. The male then fertilizes the eggs as he is pulled over the nest. After the spawning is complete, the crabs leave and the waves wash sand over the nest.

Predators

Several types of shore birds eat horseshoe crab eggs, various fish, invertebrates and sea turtles feed on the larvae, and humans catch adult horseshoe crabs to use as bait and for medical research.

Mexican Red-knee Tarantula

Posted on: February 28th, 2014 by wgoodman

Spiders are known as arachnids; scorpions also belong to this group. Although usually peaceful, when threatened a Mexican red knee will rear up to display its fangs and the bristles on its abdomen. By rubbing its back legs, hair can be flipped as a defense. These “urticating” hairs are barbed and in contact with soft tissue they dig in and cause an irritation. Tarantulas molt usually once a year. Molting of the old exoskeleton allows the spider to grow larger, gives it a completely new set of undamaged sensory and protective hairs and also gets rid of any parasite or fungus that might have started to grow on its exterior. Lost or damaged appendages are regenerated gradually with each succeeding molt, even during the adult phase. It has eight eyes positioned around the head to see both forward and backwards. They do not have great vision, so use their sensitive leg hairs for guidance. Spiders do not hear, but they have a very well-developed ability to sense vibrations, both airborne and those transmitted through the surface on which they are standing. This sensory ability is sited in a number of different receptors on their body, but especially on the appendages.

Habitat

Primarily found on the coast and rainforests of Mexico. Found in deserts and rainforests in rocky areas, near bushes and logs and around cacti.

Diet

This species of tarantula is known to feed on insects, spiders, small lizards and small mammals. Tarantula’s ambush-hunt, generally at night. The spider will inject its prey with venom through two hollow fangs. The venom serves two purposes: first is to paralyze the victim and second is to carry digestive juices that will liquefy the insides of the prey item.

Behavior

Nocturnal and solitary. Before copulation the male takes up into his palps sperm that he has deposited on a specially spun sperm web. The sperm is then implanted in the female’s storage organs and may remain there for some time. Females lay several hundred eggs, which she covers with a sticky liquid containing the sperm. The eggs are wrapped in silk and carried between the mother’s fangs. Eggs hatch between one and a half and two and a half months. Spiderlings are guarded for several weeks.

Predators

Large birds and snakes as well as habitat destruction and the pet trade are of concern for these spiders.

Channeled Whelk and Knobbed Whelk

Posted on: February 28th, 2014 by wgoodman

Whelks are large marine snails (gastropods) with spiral shells. Whelks are often confused with Conchs- both are large marine snails similar in appearance. However, conchs live in warm tropical water and are herbivores that feed on vegetation and whelks live in more temperate waters and are carnivores whose diet is mostly meat. The Knobbed Whelk is the official state shell of NJ. Most whelks (as well as most snails) are right handed or dextral. If the shell is held upright, with the spire up and the aperture facing the observer, then the aperture is on the right side. The opposite, much less common, condition is sinistral, in which the aperture is on the left of the central axis.

Habitat

Whelks are subtidal animals, meaning they live only below the low tidemark in sandy or muddy bottoms because their operculum does not tightly seal the opening of the shell so it cannot survive being exposed to the air as some intertidal animals (like mussels) can.

Diet

When hunting prey, they travel along the bay bottom using their strong foot and use their nose (or proboscis) to find these buried animals by sensing the stream of water flowing out of the clam’s feeding tubes. Once its prey is located the whelk digs down into the bay bottom to capture it. Whelks use their shell’s lip to chip and pry the valves of bivalves (clams) apart by holding it with its foot so that the ventral edges of the prey’s valves are under the outer lip of the whelk’s shell. This is similar to using a clam knife to shuck (open) a hard clam. Slow chipping continues until an opening occurs to allow the whelk to wedge its shell between the clam’s valves.When there is sufficient room, it extends its proboscis (with mouth at the end) to begin feeding.  Another method of getting at a food source (especially if the victim is not a bivalve) is that once the prey is immobilized, the whelk extends its proboscis which is equipped with a mouth and a tooth-like radula at the end. The whelk has a gland that secretes a chemical that softens calcium carbonate so the radula can efficiently be used to bore a hole in the shell of the prey. When the drilling process is completed, the whelk extends its proboscis into the prey and begins feeding.

Behavior

Whelks reproduce by sexual reproduction with internal fertilization. Some, like the channeled and knobbed whelk, produce a string of egg capsules that may be 2-3 feet long, and each capsule has 20-100 eggs inside which hatch into miniature whelks. The egg capsule allows the young whelk embryos to develop and provides protection. Once they have developed, the eggs hatch inside the capsule, and the juvenile whelks leave via an opening.

Whelks grow by using their mantle to produce calcium carbonate to extend their shell around a central axis or columella, producing turns, or whorls, as they grow. A whorl is each spiral of the shell. The final whorl, and usually the largest, is the body whorl that terminates, providing the aperture into which the snail can withdraw.

Predators

One of the whelks natural predators are the blue crab. They are also a popular human food and are often caught as bi-catch in the fisheries industry and are collected for the sea shell trade.